Phytoestrogens - What are they and do they give menopause relief?

Phytoestrogens are known to reduce menopause symptoms such as hot flushes and night sweats, two of the most reported, debilitating symptoms that affect the wellbeing of women across the menopausal transition. If you are eating a diet rich in soy, wholegrains, legumes, fruits and vegetables, you are getting phytoestrogens in your diet too. There are different types of phytoestrogens, some having more of an effect than others.

What are phytoestrogens?

Phytoestrogens are plant based oestrogens (“phyto” is greek meaning plant) that occur naturally in plants. Their chemical structure is very similar to our own oestrogen, and as a result, are able to bind to the oestrogen receptors in our body. There are three main types of phytoestrogens – isoflavones, lignins and coumestans.

Isoflavones are the most studied of the phytoestrogens, and therefore, their effects on menopausal symptoms are the most well known.

The main dietary sources of each of the types of phytoestrogens are:

Isoflavones – legumes, mainly soybeans and soy products such as tempeh, tofu, miso, soy milk as well as other legumes such as chickpeas, lentils

Lignins – flaxseed (also known as linseed), flaxseed oil, walnuts, wholegrains such as oats, barley, quinoa, rice bran and brown rice, some fruits and vegetables

Coumestans – alfalfa sprouts, clover and mung beans

How do phytoestrogens work in the body?

In perimenopause oestrogen and progesterone levels fluctuate and in post menopause they decline. This causes an increase in follicle stimulating hormone as our pituitary gland in the brain tries to talk to the ovaries to produce more oestrogen, but their activity is declining and they don’t respond. It is these hormonal changes of declining oestrogen and increasing follicle stimulating hormone that causes symptoms such as hot flushes and night sweats, vaginal dryness and the longer term health consequences of osteoporosis, heart disease and breast cancer.

Dietary phytoestrogens are digested in the small intestine, and then metabolised by our gut bacteria in the large intestine, where they are absorbed into the bloodstream, circulating until they are excreted through the urine.

Only about a third of women have a specific type of gut bacteria that can convert isoflavones, in particular soy, into an isoflavone called daidzein into a more potent form of oestrogen, called equol, which will bind to oestrogen receptors in the body and have an effect on symptoms. However, the gut bacteria needed to metabolise isoflavones, is more prominent in Asian women (conversion of isoflavone → daidzein → equol). In fact, more than 50% of Asian women and less than 20% in Caucasian women. This is most likely due to the fact that the average consumption of isoflavones in Asian countries is between 15-50mg/day and forms part of the whole eating pattern, and in Western countries, it is only 2mg/day, where processed foods are consumed more regularly in favour of soy, wholegrains, legumes, fruits and vegetables.

The research indicates on average, women should be consuming 50mg/day of isoflavones in particular, to see health effects. It is important to note that there is better bioavailability of isoflavones in whole soybeans compared to processed soy products. When choosing soy products, make sure the ingredient list states whole soybeans and not soy isolate to make sure that you are getting all the isoflavones available. It is also very important to be consuming at least thirty different colourful vegetables every week, as they not only provide fibre, but also act as prebiotics (food) for your gut bacteria, which over time will increase the numbers and types of gut bacteria you have. This will give you a greater chance of isoflavones and soybeans converting to equol and menopause symptom relief.

Should you try dietary phytoestrogens?

The majority of scientific evidence to date supports that phytoestrogens are beneficial for perimenopause symptoms, such as hot flushes and night sweats, and could be an alternative to hormone replacement therapy. There is also evidence for a protective effect for bone health, heart disease, blood sugar, triglyceride and cholesterol regulation. There is little evidence in the research to suggest that there would be a benefit for those symptoms in postmenopause at this stage, however, eating a diet high in phytoestrogens also means a diet high in fibre, vitamins and minerals, and the health effects as mentioned above. I say give it a go anyway!

If you are needing any guidance with your diet in menopause, send me an email or apply for a discovery call to discuss further.